Patent GB-1287219-A (GB)
Title: Printer
Inventor: SCHAEFER JOHN O'NEIL
IPC: B41J25/02
Filed: 1970-12-07
Abstract: 1287219 Typewriters INTERNATIONAL BUSINESS MACHINES CORP 7 Dec 1970 [22 Dec 1969] 57954/70 Heading B6F In a printer having a type element (17, Figs. 1, 2) and means for positioning the type element for selection of a character to be printed, the positioning means is also effective to select a non-print function in conjunction with mode selection means which can be conditioned to permit or prevent impact action of the type element. Character printing mode of operation.-On depression of a character key (21, Fig. 2) a cam 51, Figs. 3 and 4, on a shaft 15 rotates one revolution and pivots a lever 54 about a rod 55 coupled to a type element rocker member 40 through a pin 56 to cause impression, and a cam 80, Fig. 4 (a bottom plan view) acts on an arm 81 to disengage escapement pawls 73, 101 from a rack 16 for letter spacing action of a type carriage 14. Character selection is achieved by appropriate rotation and tilt of a type element supporting post 45 through a rotation pulley 46 and a tilt pulley sector 47 under control of combination and aggregation type selection mechanisms, the combination code being derived from key operated interposers (22, Fig. 2) bearing tabs (27). Non-print function mode of operation.-On depression of a non-print function key, a bail 36, Figs. 3 and 4, is rocked through an additional tab (29, Fig. 2) on the corresponding interposer, the bail 36 acting to unlatch an arm 62 carrying the rod 55 so that on rotation of the cam 51 the lever 54 idles about the pin 56 and no impression action results. The non-print function selected is achieved by appropriate movement of the pulley 46 and pulley sector 47. Word-spacing action.-For word spacing, no rotation or tilt of the type element is selected, so that the arm 81 performs its usual stroke to operate the escapement mechanism, while the bail 36 disengages the impression mechanism. Case-shift and line-spacing actions.-For case shift or line space operations, disengagement of the escapement pawls 73, 101 is not required, so a three unit rotation of pulley 46 in a counterclockwise direction (as viewed in Fig. 4) is selected, whereby the upper (in Fig. 4) of two pins 85 mounted on a disc 84 fixed to the pulley 46 engages a projection 87 on a slide 86 previously displaced by bail 36, and thereby pivots the arm 81 from its normal position 83 to an alternative position 89 in which it is ineffective to lift the escapement pawls 73, 101 from the rack 16. The case shift or line space function is performed by other means (not shown). Tabulation action.-For tabulation, the pulley 46 is rotated five units counterclockwise, whereby the arm 81, through slide 86, is pivoted to a position 97 wherein it is effective to engage a tabulation lever 91 with the result that the escapement pawls 73, 101 are disengaged from the rack 16 through a lug 92, and a tabulation central stop 95 is positioned in alignment with any set tab stops 96. When the stop 95 strikes a stop 96, the lever 91 is forced to the right, whereby the lug 92 is disengaged from the pawl 73 so that the pawl 73 is free to re-engage the rack 16, and lever 91 is disengaged from a latch (93, Fig. 6) holding it in operative position during travel of the type carriage 14. Back-spacing action.-For back-spacing, the pulley 46 is rotated three units to prevent letter-spacing escapement operation as for case shift or line-spacing, and the pulley sector 47 is rotated three units whereby a pin 114, Fig. 3, thereon pivots a lever 110, Figs. 3 and 4, through a lug 113 whereby a tab 115, Fig. 4, thereon engages a projection 109 on an arm 104 previously displaced by bail 36. A cam 106 acting through a follower 107 pivots the arm 104 about the point of engagement between tab 115 and projection 109, so that end 105 of arm 104 bears against a lug 101b on pawl 101 and the carriage is urged to the right, pawl 73 holding the carriage in its displaced position. Carriage-return action.-For carriage return, the cam 51 is partially rotated to a position wherein the arm 81 holds the pawls 73, 101 out of engagement with the rack 16, an elongated tab (121, Fig. 2) on the carriage-return interposer acting on a clutch disengaging member (129) to disengage the cycle clutch (25) after such partial rotation. The clutch is re-engaged to complete a cycle of rotation of the shaft 15 and cam 51 when a counterstop (133, Fig. 8) on the carriage 14 strikes a margin stop (130) to displace a rack (131) whereby the clutch disengaging member (129) is released from the clutch.